Celebrating its fourth anniversary, the location-based social networking service Foursquare today pushed a major new version of its mobile app, bringing out new features that tap over 3.5 billion check-ins users have made on the service thus far. “With the new Foursquare 6.0, we’re crunching all our data to show the best of what’s nearby, anywhere in the world, the second you open up the app,” the team wrote in a blog post Wednesday. Here’s what’s new…

The new Foursquare 6.0 offers more insights than ever into what your friends are doing and the places you may be interested in exploring.

We’re constantly crunching our data to customize the recommendations you see, based on the time of day, how familiar you are with the neighborhood, and what’s popular at the moment.

You’ll immediately notice that the search bar is now prominently placed front and center to emphasize Foursquare’s data-mining ability stemming from combing through the billions of check-ins. Right below it is a map with nearby friends and interesting places highlighted (tap on the map to expand it).

You can search Explore from the top of the app “as soon as you open it up,” the company notes. In addition to the generic terms such as “dessert” or “park”, you can also browse a type of place such as “Nightlife” or tap “Best Nearby” to see the top Foursquare picks in your current area.

In addition to search, Foursquare 6.0 also curates a list of the best of what’s nearby, including the best places to visit, venues to explore and events happening around you.

In Paris for the first time? We’ll show you the top sights and attractions, approved by local check-ins.

In a familiar neighborhood? We can tell you about an up and coming restaurant that just opened up a few blocks away.

With this feature, I bet there many developers who create tourist guides for mobile platforms will be dissatisfied with Foursquare stepping on their home turf.

I also love the new the new check-in button (see the screenies top of post).

By the way, they didn’t remove the Leaderboard feature.

So if you’re still eager to compete with friends on check-ins, swipe to the left, tap the top icon, then navigate to Profile & History and then Stats.